2.2 Audio processing board for the tms320f2812 dsp

Overview

This module describes an audio signal processing daughtercard that has been designed for use with a Texas Instruments TMS320F2812 DSP. The daughtercard is meant to be used with the corresponding eZdsp kit from Spectrum Digital . This card was designed to teach students about various functions of the TMS320C2000 series of DSPs in a practical setting, and to allow them to perform basic audio experiments. The figure below shows a simplified block diagram of the audio daughtercard, the features of which will be discussed in the next section.

Technical description

System features

The audio daghtercard has the following features and functionality:

Audio daughtercard features list

• Stereo analog input with maximum input voltage of 500mVpp.
• Amplification to 0 to 3V range of TMS320F2812 12-bit ADC.
• Programmable pre-ADC anti-alias filtering using the MAX7414 , a 5th order lowpass Butterworth filter with a tunable $f_{\mathrm{c}}$ from 1 to 15kHz.
• 2 12-bit DAC Channels using the TLV5638 .
• Programmable post-DAC filtering using the MAX7414 .
• Output power amplification capabale of driving 0.7W into an 8 Ohm load, using the TPA721 .
• 2 Potentiometers connected to ADC inputs.
• Pushbutton input capable of interrupting the DSP.
• Pushbuttons to shutdown power amplification
• 8 element LED array
• DSP control over the following: pre-ADC and post-DAC filter shutdown, pre-ADC and post-DAC filter $f_{\mathrm{c}}$ , and power amplifier shutdown.